AUTOMOTIVE ELECTRICAL CIRCUITS AND WIRING

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CELL VOLTAGE TEST. The cell voltage test will let you know if the battery is discharged or defective. Like a hydrometer cell test, if the voltage reading on one or more cells is .2 volts or more lower than the other cells, the battery must be replaced. To perform a cell voltage test (fig. 2-9), use a low voltage reading voltmeter with special cadmium (acid resistant metal) tips. Insert the tips into each cell, starting at one end of the battery and work your way to the other. Test each cell carefully. If the cells are low, but equal, recharging usually will restore the battery. If cell voltage readings vary more than .2 volts, the battery is BAD. Figure 2-8.- Battery voltage test performed with a battery tester. Figure 2-9.- Cell voltage test. BATTERY DRAIN TEST.- A battery drain test checks for abnormal current draw with the ignition off. If a battery goes dead without being used, you need to check for a current drain. AUTOMOTIVE ELECTRICAL CIRCUITS AND WIRING 18/ 101
To perform a battery drain test, set up an ammeter, as shown in figure 2-10. Pull the fuse if the vehicle has a dash clock. Close all doors and trunk (if applicable). Then read the ammeter. If everything is off, there should be a zero reading. Any reading indicates a problem. To help pinpoint the problem, pull fuses one at a time until there is a zero reading on the ammeter. This action isolates the circuit that has the problem. BATTERY CAPACITY TEST.- A battery load test, also termed a battery capacity test, is the best method to check battery condition. The battery load test measures the current output and performance of the battery under full current load. It is one of the most common and informative battery tests used today. Before load testing a battery, you must calculate how much current draw should be applied to the battery. If the ampere-hour rating of the battery is given, load the battery to three times its amp-hour rating. For example, if the battery is rated at 60 amp-hours, test the battery at 180 amps (60 x 3 = 180). The majority of the batteries are now rated in SAE cold-cranking amps, instead of amp-hours. To determine the load test for these batteries, divide the cold-crank rating by two. For example, a battery with 400 coldcranking amps rating should be loaded to 200 amps (400 ÷ 2 = 200). Connect the battery load tester, as shown in figure 2-11. Turn the control knob until the ammeter reads the correct load for your battery. Figure 2-10.- Battery drain test setup. After checking the battery charge and finding the amp load value, you are ready to test battery output. Make sure that the tester is connected properly. Turn the load control knob until the ammeter reads the correct load for your battery. Hold the load for 15 seconds. Next, read the voltmeter while the load is applied. AUTOMOTIVE ELECTRICAL CIRCUITS AND WIRING 19/ 101
Page 1 and 2: AUTOMOTIVE ELECTRICAL CIRCUITS AND
Page 3 and 4: AUTOMOTIVE ELECTRICAL CIRCUITS AND
Page 5 and 6: It must help the charging system pr
Page 7 and 8: BATTERY CASE, COYER, AND CAPS. The
Page 9 and 10: BATTERY CAPACITY The capacity of a
Page 11 and 12: smaller charge is needed. As the ba
Page 13 and 14: the water slowly, stirring gently b
Page 15 and 16: the terminals just enough to secure
Page 17: Figure 2-6.- Battery leakage test.
Page 21 and 22: must be used to convert from altern
Page 23 and 24: charge, the line voltage will incre
Page 25 and 26: Figure 2-14.- Schematic wiring diag
Page 27 and 28: short is present, the steel strip w
Page 29 and 30: Figure 2-20.- Testing an armature f
Page 31 and 32: The fingers on one of the claw-shap
Page 33 and 34: A cross-sectional view of a typical
Page 35 and 36: The electronic voltage regulators u
Page 37 and 38: If the ohmmeter reading is low or t
Page 39 and 40: After completing the required test
Page 41 and 42: CAUTION Follow the manufacturer's d
Page 43 and 44: armature and the field; the attract
Page 45 and 46: gears engage and when the engine ki
Page 47 and 48: voltage from the battery is often t
Page 49 and 50: eduction drive head may rotate as m
Page 51 and 52: Once the starter is checked and rep
Page 53 and 54: The ignition circuit is actually ma
Page 55 and 56: Figure 2-43.- Ignition switch and p
Page 57 and 58: DISTRIBUTOR CAP.- The distributor c
Page 59 and 60: SPARK PLUG WIRES The spark plug wir
Page 61 and 62: The components of an electronic ign
Page 63 and 64: As speed increases, centrifugal for
Page 65 and 66: Spark Plugs and Spark Plug Wires Ba
Page 67 and 68: Figure 2-50.- Ash fouled. When a sp
Page 69 and 70:
A common problem arises when a CARB
Page 71 and 72:
ELECTRONIC IGNITION DISTRIBUTOR SER
Page 73 and 74:
After the initial ignition timing,
Page 75 and 76:
Figure 2-56.-( A) Single-contact bu
Page 77 and 78:
Figure 2-60.- Blackout light/ headl
Page 79 and 80:
To ensure that the headlights are p
Page 81 and 82:
Figure 2-65.- Blackout driving ligh
Page 83 and 84:
The turn signal flasher unit (fig.
Page 85 and 86:
EMERGENCY LIGHT SYSTEM The emergenc
Page 87 and 88:
operation, the voltage indicated on
Page 89 and 90:
The THERMOSTATIC FUEL GAUGE, SELF-R
Page 91 and 92:
A pressure gauge is used widely in
Page 93 and 94:
Figure 2-82.- Types of sending unit
Page 95 and 96:
Electronic Speedometers and Tachome
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AUTOMOTIVE WIRING Learning Objectiv
Page 99 and 100:
Figure 2-86.- A typical wiring harn
Page 101:
Figure 2-89.- Wiring diagram symbol
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AUTOMOTIVE ELECTRICAL CIRCUITS AND WIRING

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